text: // -*- c++ -*-
  /*
   * OGLFT: A library for drawing text with OpenGL using the FreeType library
   * Copyright (C) 2002 lignum Computing, Inc. <oglft@lignumcomputing.com>
   * $Id: OGLFT.h.cmake 107 2008-04-25 09:29:24Z brevilo $
   *
   *
   * Contains small modifications by Mario Kleiner. Search for text "MK" for
   * comments on the minimal changes needed to provide Unicode support while
   * removing dependencies on the QT toolkit.
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   */
  #ifndef OGLFT_H
  #define OGLFT_H
  
  // CMake activates these definitions.
  /* #undef ENABLE_QT */
  /* #undef ENABLE_GLE */
  /* #undef GLU_TESS_CALLBACK_TRIPLEDOT */
  /* #undef HAVE_OPENGL_DIR */
  // Convert to our old options.
  #if !defined(ENABLE_QT)
  #define ENABLE_QT
  #endif
  #if !defined(ENABLE_GLE)
  #define OGLFT_NO_SOLID
  #endif
  
  #include <cmath>
  #include <map>
  #include <list>
  #include <vector>
  
  #ifdef WIN32
  #include <windows.h>
  #endif
  
  #ifdef HAVE_OPENGL_DIR
  #include <OpenGL/gl.h>
  #include <OpenGL/glu.h>
  #else
  #include <GL/gl.h>
  #include <GL/glu.h>
  #endif
  
  #ifndef OGLFT_NO_SOLID
  #ifdef HAVE_OPENGL_DIR
  #include <OpenGL/gle.h>
  #else
  #include <GL/gle.h>
  #endif
  #endif
  
  #ifndef OGLFT_NO_QT
  // MK changed to OGLFT_QT_VERSION 0
  #define OGLFT_QT_VERSION 0
  #if OGLFT_QT_VERSION == 3
  #include <qstring.h>
  #include <qcolor.h>
  #elif OGLFT_QT_VERSION == 4
  #include <QString>
  #include <QColor>
  // MK changed to include qstringqcharemulation.h on OGLFT_QT_VERSION == 0
  #elif OGLFT_QT_VERSION == 0
  #include <qstringqcharemulation.h>
  #endif
  #endif
  
  #include <ft2build.h>
  #include FT_FREETYPE_H
  #include FT_GLYPH_H
  #include FT_OUTLINE_H
  #include FT_TRIGONOMETRY_H
  
  #ifdef _MSC_VER
  #ifdef OGLFT_BUILD
  #define OGLFT_API __declspec(dllexport)
  #else
  #define OGLFT_API __declspec(dllimport)
  #endif
  #else
  #define OGLFT_API
  #endif
  
  //! All of OGLFT C++ objects are in this namespace.
  
  namespace OGLFT {
  
    //! Thanks to DesCartes, I'd consider these manifest constants.
    enum Coordinates {
      X, //!< The X component of space
      Y, //!< The Y component of space
      Z, //!< The Z component of space
      W  //!< The projection component of space
    };
  
    //! Who to credit? Newton? I'd consider these manifest constants.
    enum ColorSpace {
      R, //!< The Red component of a color
      G, //!< The Green component of a color
      B, //!< The Blue component of a color
      A, //!< The Alpha (or transparency) of a color
    };
  
    //! Callback from GLU tessellation routines.
  #ifdef GLU_TESS_CALLBACK_TRIPLEDOT
    typedef GLvoid (*GLUTessCallback)(...);
  #else
    typedef GLvoid (*GLUTessCallback)();
  #endif
  
    //! The FreeType library instance.
    /*!
     * The FreeType library has a single, global instance of a library
     * handle.  This reference is used to load font faces. This detail
     * is generally hidden from the user of OGLFT, however, it
     * can be useful to get the FT_Library instance if you want to open
     * a font file yourself, either from disk or embedded in the program.
     */
    class Library {
    public:
      /*!
       * The FreeType library's library handle is only available through this
       * accessor method.
       * \return the global OGLFT FreeType library handle.
       */
      static OGLFT_API FT_Library& instance ( void );
  
    protected:
      /*!
       * The constructor for this class is automatically called when
       * this library is loaded. Access the instance through the instance()
       * method.
       */
      OGLFT_API Library ( void );
      /*!
       * This destructor is automatically called when the program exits.
       */
      OGLFT_API ~Library( void );
  
    private:
      static Library library;
      static FT_Library library_;
    };
  
    //! Advance describes the "advance" of a glyph, namely the distance in
    //! model space at which the NEXT glyph should be drawn. This class exists
    //! to assist the computation of string metrics.
    struct OGLFT_API Advance {
      float dx_;  //!< Advance increment in the X direction.
      float dy_;  //!< Advance increment in the Y direction.
  
      //! Default constructor. An otherwise uninitialized Advance contains zeros.
      Advance ( float dx = 0, float dy = 0 ) : dx_( dx ), dy_( dy )
      {}
  
      //! Initialize an advance from a FreeType advance member.
      Advance ( FT_Vector v )
      {
        dx_ = v.x / 64.f;
        dy_ = v.y / 64.f;
      }
  
      //! Increment Advance with a FreeType advance member.
      //! \return a reference to oneself.
      Advance& operator+= ( const FT_Vector v )
      {
        dx_ += v.x / 64.f;
        dy_ += v.y / 64.f;
        return *this;
      }
    };
  
    //! Describe the metrics of a glyph or string relative to the origin
    //! of the first character
    struct OGLFT_API BBox {
      float x_min_;     //!< The left-most position at which "ink" appears.
      float y_min_;     //!< the bottom-most position at which "ink" appears.
      float x_max_;     //!< The right-most position at which "ink" appears.
      float y_max_;     //!< The top-most position at which "ink" appears.
      Advance advance_; //!< The (total) advancement
  
      //! Default constructor is all zeros.
      BBox () : x_min_( 0 ), y_min_( 0 ), x_max_( 0 ), y_max_( 0 )
      {}
  
      /*!
       *(Partially) initialize a BBox from a FreeType bounding box member.
       *(The advancement is initialized to zero by its default constructor).
       * \param ft_bbox a FreeType bounding box as retrieved from
       * \c FT_Glyph_Get_CBox.
       */
      BBox ( FT_BBox ft_bbox )
      {
        x_min_ = ft_bbox.xMin / 64.f;
        y_min_ = ft_bbox.yMin / 64.f;
        x_max_ = ft_bbox.xMax / 64.f;
        y_max_ = ft_bbox.yMax / 64.f;
      }
  
      //! Scale the bounding box by a constant.
      //! \param k a constant to scale the bounding box by.
      //! \return a reference to oneself.
      BBox& operator*= ( float k )
      {
        x_min_ *= k;
        y_min_ *= k;
        x_max_ *= k;
        y_max_ *= k;
        advance_.dx_ *= k;
        advance_.dy_ *= k;
  
        return *this;
      }
  
      /*!
       * Merge a bounding box into the current one (not really addition).
       * Each time a BBox is "added", the current BBox is expanded to include
       * the metrics of the new BBox. May only work for horizontal fonts, though.
       * \param b the bounding box to merge.
       * \return a reference to oneself.
       */
      BBox& operator+= ( const BBox& b )
      {
        float new_value;
  
        new_value = b.x_min_ + advance_.dx_;
        if ( new_value < x_min_ ) x_min_ = new_value;
  
        new_value = b.y_min_ + advance_.dy_;
        if ( new_value < y_min_ ) y_min_ = new_value;
  
        new_value = b.x_max_ + advance_.dx_;
        if ( new_value > x_max_ ) x_max_ = new_value;
  
        new_value = b.y_max_ + advance_.dy_;
        if ( new_value > y_max_ ) y_max_ = new_value;
  
        advance_.dx_ += b.advance_.dx_;
        advance_.dy_ += b.advance_.dy_;
  
        return *this;
      }
    };
  
    //! During tesselation of a polygonal Face (outline, filled or solid),
    //! an object which implements this interface can be used to compute a
    //! different color for each vertex.
    class OGLFT_API ColorTess {
    public:
      virtual ~ColorTess ( void ) {}
      //! Compute a color for this position. Note that the position is
      //! in the glyph's local coordinate system.
      //! \param p vertex position in glyph's local coordinate system. Argument is
      //! a GLdouble[3].
      //! \return GLfloat[4] (RGBA) color specification.
      virtual GLfloat* color ( GLdouble* p ) = 0;
    };
  
    //! During tesselation of a polygonal Face (outline, filled or solid),
    //! an object which implements this interface can be used to compute a
    //! different texture coordinate for each vertex.
    class OGLFT_API TextureTess {
    public:
      virtual ~TextureTess ( void ) {}
      //! Compute a texture coordinate for this position. Note that the
      //! position is in the glyph's local coordinate system.
      //! \param p vertex position in glyph's local coordinate system. Argument is
      //! a GLdouble[3].
      //! \return GLfloat[2] (s,t) texture coordinates.
      virtual GLfloat* texCoord ( GLdouble* p ) = 0;
    };
  
    //! The argument to setCharacterDisplayLists is an STL vector of
    //! OpenGL display list names (GLuints).
    typedef std::vector<GLuint> DisplayLists;
  
    //! A convenience definition of an iterator for display list vectors.
    typedef DisplayLists::const_iterator DLCI;
  
    //! A convenience definition of an iterator for display list vectors.
    typedef DisplayLists::iterator DLI;
  
    //! A face (aka font) used to render text with OpenGL.
    /*!
     * This is an abstract class, but it does define most the functions that
     * you are likely to call to manipulate the rendering of the text.
     */
    class Face {
    public:
      //! Thanks to the standard formerly known as PHIGS. Horizontal text
      //! justification constants.
      enum OGLFT_API HorizontalJustification {
        LEFT,   //!< Left justified justification of text
        ORIGIN, //!< Natural origin alignment of text (default)
        CENTER, //!< Center justified alignment of text
        RIGHT   //!< Right justified alignment of text
      };
  
      //! Thanks to the standard formerly known as PHIGS. Vertical text
      //! justification constants.
      enum OGLFT_API VerticalJustification {
        BOTTOM,   //!< Descender alignment of text
        BASELINE, //!< Baseline alignment of text (default)
        MIDDLE,   //!< Centered alignment of text
        TOP       //!< Ascender justification of text
      };
  
      //! Control how OpenGL display lists are created for individual glyphs.
      //! The default mode is to create display lists for each glyph as it
      //! is requested. Therefore, the Face drawing routines cannot themselves
      //! be called from within an open display list. In IMMEDIATE mode,
      //! cached glyphs will be drawn if available, otherwise the FreeType
      //! data for a glyph is re-rendered each time.
      enum OGLFT_API GlyphCompileMode {
        COMPILE,    //!< Compile new glyphs when seen for the first time.
        IMMEDIATE   //!< Do not \em create display lists for glyphs.
      };
  
    private:
      //! We allow a Face to be constructed either from a file name
      //! or passed in as an already opened FreeType FT_Face. In the case
      //! of the later (already opened), we don't close the FT_Face on
      //! destruction. This way you can share FT_Faces between related
      //! OGLFT faces. Also, we're experimenting with being able to use
      //! multiple FT_Faces in a single OGLFT Face, so this is represented
      //! as a data structure.
      struct FaceData {
        FT_Face face_;
        bool free_on_exit_;
        FaceData ( FT_Face face, bool free_on_exit = true )
  	: face_( face ), free_on_exit_( free_on_exit )
        {}
      };
    protected:
      //! The FreeType face - experimentally, this is now an array of
      //! faces so that we can handle a wider range of UNICODE points
      //! in case a face doesn't cover the points of interest.
      std::vector< FaceData > faces_;
  
      //! Did a font load OK?
      bool valid_;
  
      //! Glyph display list creation mode.
      enum GlyphCompileMode compile_mode_;
  
      //! Nominal point size.
      float point_size_;
  
      //! Display resolution in pixels per inch.
      FT_UInt resolution_;
  
      //! Does rendering text affect the MODELVIEW matrix?
      bool advance_;
  
      //! Foreground color (I really wanted to avoid this, but not really
      //! possible without state queries, which you can't put into
      //! display lists. Anyway, you'll be able to get even more fancy
      //! by passing in a function to map the color with, so why balk at
      //! this?)
      GLfloat foreground_color_[4];
  
      //! Background color (what modes would use this?)
      GLfloat background_color_[4];
  
      //! PHIGS-like horizontal positioning of text.
      enum HorizontalJustification horizontal_justification_;
  
      //! PHIGS-like vertical positioning of text.
      enum VerticalJustification vertical_justification_;
  
      //! Rotate an entire string in the Z plane
      GLfloat string_rotation_;
  
      //! Let the user decide which character to use as the rotation reference.
      //! Use "o" by default, I suppose.
      FT_UInt rotation_reference_glyph_;
  
      //! The rotation reference character could be in any face.
      FT_Face rotation_reference_face_;
  
      //! These are the translation offsets provided by the rotation reference
      //! character; for whom, we've discovered, only the Y position is relevant.
      GLfloat rotation_offset_y_;
  
      //! Type of the cache of defined glyph to display list mapping.
      typedef std::map< FT_UInt, GLuint > GlyphDLists;
  
      //! A convenience definition of the iterator over the glyph to display
      //! list map.
      typedef GlyphDLists::const_iterator GDLCI;
  
      //! A convenience definition of the iterator over the glyph to display
      //! list map.
      typedef GlyphDLists::iterator GDLI;
  
      //! Cache of defined glyph display lists
      GlyphDLists glyph_dlists_;
  
      //! The user can supply an array of display list which are invoked
      //! before each glyph is rendered.
      DisplayLists character_display_lists_;
  
    public:
      /*!
       * Construct a Face by loading a font from the given file.
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      Face ( const char* filename, float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * Construct a Face by loading a font from the given memory location.
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      Face ( const FT_Byte* data_base, const FT_Long data_size,
  	   float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * Alternatively, the user may have already opened a face and just
       * wants to draw with it. This is useful for Multiple Master fonts or
       * combining multiple files to increase UNICODE point coverage.
       * \param face open Freetype FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      Face ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * Deleting a Face frees its FreeType face (and anything else it's
       * styles have allocated).
       */
      virtual ~Face ( void );
  
      /*!
       * Let the user test to see if the font was loaded OK.
       * \return true if the FT_Face was successfully created.
       */
      bool isValid ( void ) const { return valid_; }
  
      /*!
       * Add another FT_Face to the OGLFT Face. Generally used to add more
       * coverage of UNICODE points (at least that's the plan). This
       * routine takes a filename and takes ownership of the FT_Face.
       * \param filename name of file containing font face data.
       * \return true if face was successfully added.
       */
      bool addAuxiliaryFace ( const char* filename );
  
      /*!
       * Add another FT_Face to the OGLFT Face. Generally used to add more
       * coverage of UNICODE points (at least that's the plan). This
       * routine takes a memory location and takes ownership of the FT_Face.
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \return true if face was successfully added.
       */
      bool addAuxiliaryFace ( const FT_Byte* data_base, const FT_Long data_size );
  
      /*!
       * Add another FT_Face to the OGLFT Face. Generally used to add more
       * coverage of UNICODE points (at least that's the plan). This
       * routine takes an already open FT_Face. The user is responsible
       * for clean up.
       * \param face open FreeType FT_Face
       * \return true if face was successfully added.
       */
      bool addAuxiliaryFace ( FT_Face face );
  
      /*!
       * By default, each time a new character is seen, its glyph is rendered
       * into a display list. This means that a display list cannot already
       * be open (since OpenGL doesn't allow nested display list creation).
       * Rendering can be set into immediate mode in which case glyphs are
       * rendered from display lists if available, but are otherwise generated
       * anew each time.
       * \param compile_mode the new compile mode.
       */
      void setCompileMode ( enum GlyphCompileMode compile_mode )
      {
        compile_mode_ = compile_mode;
      }
  
      /*!
       * \return the current glyph compile mode.
       */
      enum GlyphCompileMode compileMode ( void ) const { return compile_mode_; }
  
      /*!
       * For the rasterized styles (Monochrome, Grayscale, Translucent, Texture),
       * glyphs are rendered at the pixel size given by:
       *
       * point_size [pts] * / 72 [pts/in] * resolution [dots/in] = [dots].
       *
       * For the polygon styles (Outline, Filled, Solid), the "nominal" size of
       * the glyphs is:
       *
       * point_size[pts] / 72 [pts/in] * resolution [dots/in]
       * / units_per_EM [font unit/EM] = [dots * EM].
       *
       * If the MODELVIEW and PROJECTION matrices are such that one screen pixel
       * corresponds to one modeling unit, then polygonal Faces will
       * be the same size as raster Faces.
       *
       * Note that changing the point size after Face creation will invalidate
       * the cache of OpenGL display lists and any other information which
       * the individual styles have cached.
       * \param point_size the new point size in points (1/72-th inch).
       */
      void setPointSize ( float point_size );
  
      /*!
       * \return the current point size.
       */
      float pointSize ( void ) { return point_size_; }
  
      /*!
       * For the rasterized styles (Monochrome, Grayscale,
       * Translucent, Texture), the exact rendered size of the glyphs depends on
       * the resolution of the display (as opposed to the polygon styles
       * whose size is controlled by the viewing matrices). The Texture
       * style is slightly different because the glyphs are texture-mapped
       * onto an arbitrary rectangle; here, the resolution only controls
       * how accurately the glyph is rendered.
       * \param resolution the resolution in DPI (dots per inch).
       */
      void setResolution ( FT_UInt resolution );
  
      /*!
       * \return the current raster resolution.
       */
      FT_UInt resolution ( void ) { return resolution_; }
  
      /*!
       * If advance is true, then the changes made to the MODELVIEW matrix
       * to render a string are allowed to remain. Otherwise, the library
       * pushes the current MODELVIEW matrix onto the matrix stack, renders
       * the string and then pops it off again. Rendering a character always
       * modifies the MODELVIEW matrix.
       * \param advance whether or not the MODELVIEW matrix should be left
       * translated by the advancement of a rendered string.
       */
      void setAdvance ( bool advance ) { advance_ = advance; }
  
      /*!
       * \return the advance value.
       */
      bool advance ( void ) const { return advance_; }
  
      /*!
       * This is the nominal color of the glyphs. A lot of other things
       * can alter what you actually see! Note that changing the foreground
       * color invalidates the glyph cache.
       * \param red the red component of the foreground color.
       * \param green the green component of the foreground color.
       * \param blue the blue component of the foreground color.
       * \param alpha the alpha component of the foreground color.
       */
      void setForegroundColor ( GLfloat red = 0.0,
  			      GLfloat green = 0.0,
  			      GLfloat blue = 0.0,
  			      GLfloat alpha = 1.0 );
  
      /*!
       * This is the nominal color of the glyphs. A lot of other things
       * can alter what you actually see! Note that changing the foreground
       * color invalidates the glyph cache.
       * \param foreground_color an array of 4 values corresponding to the
       * red, green, blue and alpha components of the foreground color.
       */
      void setForegroundColor ( const GLfloat foreground_color[4] );
  #ifndef OGLFT_NO_QT
      /*!
       * This is the nominal color of the glyphs. A lot of other things
       * can alter what you actually see! Note that changing the foreground
       * color invalidates the glyph cache.
       * \param foreground_color the foreground color as an unsigned int.
       */
      void setForegroundColor ( const QRgb foreground_color );
  #endif /* OGLFT_NO_QT */
      /*!
       * \return the red component of the foreground color
       */
      GLfloat foregroundRed ( void ) const { return foreground_color_[R]; }
      /*!
       * \return the green component of the foreground color
       */
      GLfloat foregroundGreen ( void ) const { return foreground_color_[G]; }
      /*!
       * \return the blue component of the foreground color
       */
      GLfloat foregroundBlue ( void ) const { return foreground_color_[B]; }
      /*!
       * \return the alpha component of the foreground color
       */
      GLfloat foregroundAlpha ( void ) const { return foreground_color_[A]; }
  
      /*!
       * This is the nominal background color of the glyphs. A lot of other things
       * can alter what you actually see! Note that changing the background
       * color invalidates the glyph cache.
       * \param red the red component of the background color.
       * \param green the green component of the background color.
       * \param blue the blue component of the background color.
       * \param alpha the alpha component of the background color.
       */
      void setBackgroundColor ( GLfloat red = 1.0,
  			      GLfloat green = 1.0,
  			      GLfloat blue = 1.0,
  			      GLfloat alpha = 0.0 );
  
      /*!
       * This is the nominal background color of the glyphs. A lot of other things
       * can alter what you actually see! Note that changing the background
       * color invalidates the glyph cache.
       * \param background_color an array of 4 values corresponding to the
       * red, green, blue and alpha components of the background color.
       */
      void setBackgroundColor ( const GLfloat background_color[4] );
  #ifndef OGLFT_NO_QT
      /*!
       * This is the nominal background color of the glyphs. A lot of other things
       * can alter what you actually see! Note that changing the background
       * color invalidates the glyph cache.
       * \param background_color the background color as an unsigned int.
       */
      void setBackgroundColor ( const QRgb background_color );
  #endif /* OGLFT_NO_QT */
      /*!
       * \return the red component of the background color
       */
      GLfloat backgroundRed ( void ) const { return background_color_[R]; }
      /*!
       * \return the green component of the background color
       */
      GLfloat backgroundGreen ( void ) const { return background_color_[G]; }
      /*!
       * \return the blue component of the background color
       */
      GLfloat backgroundBlue ( void ) const { return background_color_[B]; }
      /*!
       * \return the alpha component of the background color
       */
      GLfloat backgroundAlpha ( void ) const { return background_color_[A]; }
  
      /*!
       * Set the individual character rotation in the Z direction.
       * \param character_rotation_z angle in degrees of z rotation.
       */
      virtual void setCharacterRotationZ ( GLfloat character_rotation_z ) = 0;
  
      /*!
       * \return the character rotation in the Z direction.
       */
      virtual GLfloat characterRotationZ ( void ) const = 0;
  
      /*!
       * The z rotation angle needs a center. Nominate a character whose
       * center is to be the center of rotation. By default, use "o".
       * \param c rotation reference character.
       */
      void setCharacterRotationReference ( unsigned char c );
  
      /*!
       * Rotate an entire string through the given angle (in the Z plane only).
       * (Somewhat pointless for the vector styles since you can do mostly
       * the same thing with the MODELVIEW transform, however, for what its
       * worth, this routine uses the FreeType rotation function to compute
       * the "proper" metrics for glyph advance.)
       * \param string_rotation angle in degrees of z rotation.
       */
      void setStringRotation ( GLfloat string_rotation );
  
      /*!
       * \return the (Z plane) string rotation angle.
       */
      GLfloat stringRotation ( void ) const { return string_rotation_; }
  
      /*!
       * Set the horizontal justification.
       * \param horizontal_justification the new horizontal justification.
       */
      void setHorizontalJustification ( enum HorizontalJustification
  				      horizontal_justification )
      {
        horizontal_justification_ = horizontal_justification;
      }
  
      /*!
       * \return the horizontal justification.
       */
      enum HorizontalJustification horizontalJustification ( void ) const
      { return horizontal_justification_; }
  
      /*!
       * Set the vertical justification.
       * \param vertical_justification the new vertical justification
       */
      void setVerticalJustification ( enum VerticalJustification
  				    vertical_justification )
      {
        vertical_justification_ = vertical_justification;
      }
  
      /*!
       * \return the vertical justification.
       */
      enum VerticalJustification verticaljustification ( void )
        const { return vertical_justification_; }
  
      /*!
       * Specify an OpenGL display list to be invoked before
       * each character in a string. Face makes a copy of the argument. Pass
       * an empty DisplayLists to disable this feature.
       * \param character_display_lists STL vector<GLuint> containing a display
       * list to invoke before each glyph in a string is drawn.
       */
      void setCharacterDisplayLists ( const DisplayLists& character_display_lists )
      {
        character_display_lists_ = character_display_lists;
      }
  
      /*!
       * \return a reference to the array of character display lists. This is
       * the live list as stored in the Face.
       */
      DisplayLists& characterDisplayLists ( void )
      { return character_display_lists_; }
  
      /*!
       * \return the height (i.e., line spacing) at the current character size.
       */
      virtual double height ( void ) const = 0;
  
      /*!
       * Compute the bounding box info for a character.
       * \param c the (latin1) character to measure.
       * \return the bounding box of c.
       */
      virtual BBox measure ( unsigned char c ) = 0;
  #ifndef OGLFT_NO_QT
      /*!
       * Compute the bounding box info for a character.
       * \param c the (UNICODE) character to measure.
       * \return the bounding box of c.
       */
      virtual BBox measure ( const QChar c ) = 0;
  #endif /* OGLFT_NO_QT */
      /*!
       * Compute the bounding box info for a string.
       * \param s the (latin1) string to measure.
       * \return the bounding box of s.
       */
      virtual BBox measure ( const char* s );
      /*!
       * Compute the bounding box info for a string without conversion
       * to modeling coordinates.
       * \param s the (latin1) string to measure.
       * \return the bounding box of s.
       */
      virtual BBox measureRaw ( const char* s );
  #ifndef OGLFT_NO_QT
      /*!
       * Compute the bounding box info for a string.
       * \param s the (UNICODE) string to measure.
       * \return the bounding box of s.
       */
      virtual BBox measure ( const QString& s );
      /*!
       * Compute the bounding box info for a real number formatted as specified.
       * \param format (see draw for valid formats)
       * \param number real number.
       * \return the bounding box of the formatted number.
       */
      virtual BBox measure ( const QString& format, double number );
      /*!
       * Compute the bounding box info for a string without conversion
       * to modeling coordinates.
       * \param s the (UNICODE) string to measure.
       * \return the bounding box of s.
       */
      virtual BBox measureRaw ( const QString& s );
  #endif /* OGLFT_NO_QT */
      /*!
       * Compile a string into an OpenGL display list for later
       * rendering.  Essentially, the string is rendered at the origin
       * of the current MODELVIEW. Note: no other display lists should
       * be open when this routine is called. Also, the Face does not
       * keep track of these lists, so you must delete them in order
       * to recover the memory.
       * \param s the (latin1) string to compile.
       * \return the display list name for the string.
       */
      GLuint compile ( const char* s );
  #ifndef OGLFT_NO_QT
      /*!
       * Compile a string into an OpenGL display list for later
       * rendering.  Essentially, the string is rendered at the origin
       * of the current MODELVIEW. Note: no other display lists should
       * be open when this routine is called. Also, the Face does not
       * keep track of these lists, so you must delete them in order
       * to recover the memory.
       * \param s the (UNICODE) string to compile.
       * \return the display list name for the string.
       */
      GLuint compile ( const QString& s );
  #endif /* OGLFT_NO_QT */
      /*!
       * Compile a single character (glyph) into an OpenGL display list
       * for later rendering. The Face \em does keep track of these
       * display lists, so do not delete them.
       * \param c the (latin1) character to compile.
       * \return the display list name for the character.
       */
      GLuint compile ( unsigned char c );
  #ifndef OGLFT_NO_QT
      /*!
       * Compile a single character (glyph) into an OpenGL display list
       * for later rendering. The Face \em does keep track of these
       * display lists, so do not delete them.
       * \param c the (UNICODE) character to compile.
       * \return the display list name for the character.
       */
      GLuint compile ( const QChar c );
  #endif /* OGLFT_NO_QT */
      /*!
       * Draw a (latin1) string using the current MODELVIEW matrix. If
       * advance is true, then the final glyph advance changes to the
       * MODELVIEW matrix are left in place.
       * \param s the (latin1) string to draw.
       */
      void draw ( const char* s );
  #ifndef OGLFT_NO_QT
      /*!
       * Draw a (UNICODE) string using the current MODELVIEW
       * matrix. If advance is true, then the final glyph advance
       * changes to the MODELVIEW matrix are left in place.
       * \param s the (UNICODE) string to draw.
       */
      void draw ( const QString& s );
  #endif /* OGLFT_NO_QT */
      /*!
       * Draw the character using the current MODELVIEW matrix. Note that
       * the MODELVIEW matrix is modified by the glyph advance. Draw a
       * string if you don't want the MODELVIEW matrix changed.
       * \param c the (latin1) character to draw.
       */
      void draw ( unsigned char c );
  
  #ifndef OGLFT_NO_QT
      /*!
       * Draw the character using the current MODELVIEW matrix. Note that
       * the MODELVIEW matrix is modified by the glyph advance. Draw a
       * string if you don't want the MODELVIEW matrix changed.
       * \param c the (UNICODE) character to draw.
       */
      void draw ( const QChar c );
  #endif /* OGLFT_NO_QT */
      /*!
       * Draw the (latin1) character at the given 2D point. Note that
       * the MODELVIEW matrix is modified by the glyph advance. Draw
       * a string if you don't want the MODELVIEW matrix changed.
       * \param x the X position.
       * \param y the Y position.
       * \param c the (latin1) character to draw.
       */
      void draw ( GLfloat x, GLfloat y, unsigned char c );
      /*!
       * Draw the (latin1) character at the given 3D point. Note that
       * the MODELVIEW matrix is modified by the glyph advance. Draw
       * a string if you don't want the MODELVIEW matrix changed.
       * \param x the X position.
       * \param y the Y position.
       * \param z the Z position.
       * \param c the (latin1) character to draw.
       */
      void draw ( GLfloat x, GLfloat y, GLfloat z, unsigned char c );
  #ifndef OGLFT_NO_QT
      /*!
       * Draw the (UNICODE) character at the given 2D point. Note that
       * the MODELVIEW matrix is modified by the glyph advance. Draw
       * a string if you don't want the MODELVIEW matrix changed.
       * \param x the X position.
       * \param y the Y position.
       * \param c the (UNICODE) character to draw.
       */
      void draw ( GLfloat x, GLfloat y, QChar c );
      /*!
       * Draw the (UNICODE) character at the given 3D point. Note that
       * the MODELVIEW matrix is modified by the glyph advance. Draw
       * a string if you don't want the MODELVIEW matrix changed.
       * \param x the X position.
       * \param y the Y position.
       * \param z the Z position.
       * \param c the (UNICODE) character to draw.
       */
      void draw ( GLfloat x, GLfloat y, GLfloat z, QChar c );
  #endif /* OGLFT_NO_QT */
      /*!
       * Draw a string at the given 2D point.
       * \param x the X position.
       * \param y the Y position.
       * \param s the (latin1) string to draw.
       */
      void draw ( GLfloat x, GLfloat y, const char* s );
      /*!
       * Draw a string at the given 3D point.
       * \param x the X position.
       * \param y the Y position.
       * \param z the Z position.
       * \param s the (latin1) string to draw.
       */
      void draw ( GLfloat x, GLfloat y, GLfloat z, const char* s );
  #ifndef OGLFT_NO_QT
      /*!
       * Draw a string at the given 2D point.
       * \param x the X position.
       * \param y the Y position.
       * \param s the (UNICODE) string to draw.
       */
      void draw ( GLfloat x, GLfloat y, const QString& s );
      /*!
       * Draw a string at the given 3D point.
       * \param x the X position.
       * \param y the Y position.
       * \param z the Z position.
       * \param s the (UNICODE) string to draw.
       */
      void draw ( GLfloat x, GLfloat y, GLfloat z, const QString& s );
      /*!
       * Draw a real number per the given format at the given 2D point.
       * \param x the X position.
       * \param y the Y position.
       * \param format Like a typical printf format. Regular text is printed
       * while a '%' introduces the real number's format. Includes the
       * following format flags:
       * \li %%x.yf - floating point in field width x and precision y
       * \li %%x.ye - scientific notation in field width x and precision y
       * \li %%x.yg - pick best floating or scientific in field width x and
       *  precision y
       * \li %%p - draw as a proper fraction, e.g. 1 1/2. Note: this currently
       * requires a special font which encodes glyphs to be drawn for the
       * numerator and demoninator in the UNICODE Private Area (0xE000).
       *
       * \param number the numeric value.
       */
      void draw ( GLfloat x, GLfloat y, const QString& format, double number );
      /*!
       * Draw a real number per the given format at the given 3D point.
       * \param x the X position.
       * \param y the Y position.
       * \param z the Z position.
       * \param format Like a typical printf format. Regular text is printed
       * while a '%' introduces the real number's format. Includes the
       * following format flags:
       * \li %%x.yf - floating point in field width x and precision y
       * \li %%x.ye - scientific notation in field width x and precision y
       * \li %%x.yg - pick best floating or scientific in field width x and
       *  precision y
       * \li %%p - draw as a proper fraction, e.g. 1 1/2. Note: this currently
       * requires a special font which encodes glyphs to be drawn for the
       * numerator and demoninator in the UNICODE Private Area (0xE000).
       *
       * \param number the numeric value.
       */
      void draw ( GLfloat x, GLfloat y, GLfloat z, const QString& format,
  		double number );
  #endif /* OGLFT_NO_QT */
      /*!
       * \return the face ascender, in point units.
       */
      int ascender ( void );
  
      /*!
       * \return the face descender, in point units.
       */
      int descender ( void );
  
    protected:
      // The various styles override these routines
  
      //! Some styles, in particular the Texture, need specialized steps
      //! to compile a glyph into an OpenGL display list.
      //! \param face the FT_Face containing the glyph.
      //! \param glyph_index the index of the glyph in face.
      //! \return the display list of the compiled glyph.
      virtual GLuint compileGlyph ( FT_Face face, FT_UInt glyph_index ) = 0;
  
      //! Each style implements its own glyph rendering routine.
      //! \param face the FT_Face containing the glyph.
      //! \param glyph_index the index of the glyph in face.
      virtual void renderGlyph ( FT_Face face, FT_UInt glyph_index ) = 0;
  
      //! There is a slight different between the way in which the polygonal
      //! and raster styles select the character size for FreeType to generate.
      virtual void setCharSize ( void ) = 0;
  
      //! The different styles have different caching needs (well, really only
      //! the texture style currently has more than the display list cache).
      virtual void clearCaches ( void ) = 0;
  
      //! The polygonal and raster styles compute different values for the
      //! Z rotation offset. (It's in integer pixels for the raster styles and
      //! in floating point pixels for the polygonal styles.)
      virtual void setRotationOffset ( void ) = 0;
  
    private:
      void init ( void );
      BBox measure_nominal ( const char* s );
  #ifndef OGLFT_NO_QT
      BBox measure_nominal ( const QString& s );
      QString format_number ( const QString& format, double number );
  #endif /* OGLFT_NO_QT */
    };
  
    //! This is the base class of the polygonal styles: outline, filled and solid.
    /*!
     * In the polygonal styles, the detailed geometric outlines of the glyphs
     * are extracted from the font file and rendered as polygons.
     */
    class Polygonal : public Face {
    protected:
      //! Angle of rotation of characters relative to text orientation.
      struct {
        bool active_;
        GLfloat x_, y_, z_;
      } character_rotation_;
  
      //! The tessellation of curves is pretty crude; regardless of length,
      //! use the same number of increments (and as near as I can tell, this
      //! is more than sufficient unless the glyph takes up the whole screen).
      unsigned int tessellation_steps_;
  
      //! When curves are tessellated, we use the forward difference algorithm
      //! from Foley and van Dam for parametric curves (pg. 511 of 2nd Ed. in C).
      //! So, the step size, delta, is in the parametric variable which is always
      //! on the interval [0,1]. Therefore, delta = 1/tessellation_steps
      double delta_, delta2_, delta3_;
  
      //! For vector rendition modes, FreeType is allowed to generate the
      //! lines and arcs at the original face definition resolution. To
      //! get to the proper glyph size, the vertices are scaled before
      //! they're passed to the GLU tessellation routines.
      float vector_scale_;
  
      //! Callbacks for FreeType glyph decomposition into outlines
      FT_Outline_Funcs interface_;
  
      //! Default number of steps to break TrueType and Type1 arcs into.
      //! (Note: this looks good to me, anyway)
      static const unsigned int DEFAULT_TESSELLATION_STEPS = 4;
  
      /*!
       * VertexInfo is a private class which is used by the decomposition and
       * tessellation routines to store the vertices and other data of the glyph's
       * outline.  Because of the "impedance mismatch" between the crazy
       * 26.6 fixed point format of the FreeType library (well, don't
       * blame them; look at what they have to work with) and OpenGL's preference
       * for double precision, this simple vector has two constructors: one
       * for 26.6 format and one for direct floating point.
       *
       * VertexInfo also contains (optional) pointers to objects which
       * implement the ColorTess and TextureTess interfaces.
       */
      struct VertexInfo {
        double v_[3]; //!< Why is this double precision? Because the second
  		    //!< argument to the routine gluTessVertex is a pointer
  		    //!< to an array of doubles. Otherwise, we could use
  		    //!< single precision everywhere.
  
        //! The user can provide a ColorTess object which computes a color
        //! for each tesselated vertex.
        ColorTess* color_tess_;
  
        //! The user can provide a TextureTess object which computes texture
        //! coordinates for each tesselated vertex.
        TextureTess* texture_tess_;
  
        //! Default constructor just initializes Vertex to zero.
        //! \param color_tess optional color tesselation object.
        //! \param texture_tess optional texture tesselation object.
        VertexInfo ( ColorTess* color_tess = 0, TextureTess* texture_tess = 0 )
  	: color_tess_( color_tess ), texture_tess_( texture_tess )
        {
  	v_[X] = v_[Y] = v_[Z] = 0.;
        }
  
        /*!
         * Construct a Vertex from a point in a FreeType contour.
         * \param ft_v a FreeType FT_Vector, normally passed into the
         * the decomposition callbacks.
         * \param color_tess optional color tesselation object.
         * \param texture_tess optional texture tesselation object.
         */
        VertexInfo ( FT_Vector* ft_v, ColorTess* color_tess = 0,
  		   TextureTess* texture_tess = 0 )
  	: color_tess_( color_tess ), texture_tess_( texture_tess )
        {
  	v_[X] = (double)( ft_v->x / 64 ) + (double)( ft_v->x % 64 ) / 64.;
  	v_[Y] = (double)( ft_v->y / 64 ) + (double)( ft_v->y % 64 ) / 64.;
  	v_[Z] = 0.;
        }
  
        /*!
         * Construct a Vertex from a 2D point.
         * \param p 2D array of doubles.
         * \param color_tess optional color tesselation object.
         * \param texture_tess optional texture tesselation object.
         */
        VertexInfo ( double p[2], ColorTess* color_tess = 0,
  		   TextureTess* texture_tess = 0 )
  	: color_tess_( color_tess ), texture_tess_( texture_tess )
        {
  	v_[X] = p[X];
  	v_[Y] = p[Y];
  	v_[Z] = 0.;
        }
  
        /*!
         * Construct a Vertex from a 2D point.
         * \param x the X coordinate.
         * \param y the Y coordinate.
         * \param color_tess optional color tesselation object.
         * \param texture_tess optional texture tesselation object.
         */
        VertexInfo ( double x, double y, ColorTess* color_tess = 0,
  		   TextureTess* texture_tess = 0 )
  	: color_tess_( color_tess ), texture_tess_( texture_tess )
        {
  	v_[X] = x;
  	v_[Y] = y;
  	v_[Z] = 0.;
        }
  
        //! Treat the Vertex like a vector: Normalize its length in the
        //! usual way.
        void normalize ( void )
        {
  	double length = sqrt( v_[X] * v_[X] + v_[Y] * v_[Y] + v_[Z] * v_[Z] );
  	v_[X] /= length;
  	v_[Y] /= length;
  	v_[Z] /= length;
        }
      };
  
      /*!
       * Buffers the last control point as the outline of a glyph is
       * decomposed.
       */
      VertexInfo last_vertex_;
  
      //! Normally, we will consider a list of vertices.
      typedef std::list< VertexInfo* > VertexInfoList;
  
      //! A convenience definition of the iterator over the list of vertices.
      typedef VertexInfoList::const_iterator VILCI;
  
      //! A convenience definition of the iterator over the list of vertices.
      typedef VertexInfoList::iterator VILI;
  
      /*!
       * As curves are decomposed out of the glyph, their vertices are passed
       * along to the GLU tessellation functions. These vertices have to
       * hang around until gluTessContourEnd is called.
       */
      VertexInfoList vertices_;
  
      //! As GLU tessellation proceeds, new contours open with every call
      //! to moveTo.
      bool contour_open_;
  
      //! The user can provide a ColorTess object which computes a color
      //! for each tesselated vertex.
      ColorTess* color_tess_;
  
      //! The user can provide a TextureTess object which computes texture
      //! coordinates for each tesselated vertex.
      TextureTess* texture_tess_;
  
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Polygonal ( const char* filename, float point_size = 12,
  			  FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Polygonal ( const FT_Byte* data_base, const FT_Long data_size,
  			  float point_size = 12, FT_UInt resolution = 100);
  
      /*!
       * \param face open Freetype FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Polygonal ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * The Polygonal destructor doesn't do anything in particular.
       */
      OGLFT_API virtual ~Polygonal ( void );
  
      /*!
       * TrueType and Type1 files describe the boundaries of glyphs with
       * quadratic and cubic curves, respectively. Since OpenGL can only really
       * draw straight lines, these curves have to be tessellated. The
       * number of steps used is fixed for all glyphs in the face,
       * but can be changed through this method. Other notes: This value is
       * only applicable for Outline, Filled and Solid styles. Changing this value
       * invalidates any cached display lists for glyphs in this face.
       *
       * \param tessellation_steps the number of steps to tessellate each curved
       * segment of a glyph outline.
       */
      OGLFT_API void setTessellationSteps ( unsigned int tessellation_steps );
  
      /*!
       * \return the number of steps used to tessellate curves in the
       * polygonal font types.
       */
      OGLFT_API unsigned int tessellationSteps ( void ) const { return tessellation_steps_; }
  
      /*!
       * Set the individual character rotation in the X direction.
       * \param character_rotation_x angle in degrees of the X rotation.
       */
      OGLFT_API void setCharacterRotationX ( GLfloat character_rotation_x );
  
      /*!
       * Set the individual character rotation in the Y direction.
       * \param character_rotation_y angle in degrees of the Y rotation.
       */
      OGLFT_API void setCharacterRotationY ( GLfloat character_rotation_y );
  
      /*!
       * Set the individual character rotation in the Z direction.
       * \param character_rotation_z angle in degrees of the Z rotation.
       */
      OGLFT_API void setCharacterRotationZ ( GLfloat character_rotation_z );
  
      /*!
       * \return the character rotation in the X direction.
       */
      OGLFT_API GLfloat characterRotationX ( void ) const { return character_rotation_.x_; }
  
      /*!
       * \return the character rotation in the Y direction.
       */
      OGLFT_API GLfloat characterRotationY ( void ) const { return character_rotation_.y_; }
  
      /*!
       * \return the character rotation in the Z direction.
       */
      OGLFT_API GLfloat characterRotationZ ( void ) const { return character_rotation_.z_; }
  
      /*!
       * Set an optional color tesselation object. Each tesselated vertex
       * is passed to this object, which returns a color for that position
       * in space.
       * \param color_tess the color tesselation object.
       */
      OGLFT_API void setColorTess ( ColorTess* color_tess );
      /*!
       * \return the color tesselation object.
       */
      OGLFT_API ColorTess* colorTess ( void ) const { return color_tess_; }
      /*!
       * Set an optional texture coordinate tesselation object. Each
       * tessellated vertex is passed to this object, which returns
       * texture coordinates for that position in space.
       * \param texture_tess the texture coordinate tesselation object.
       */
      OGLFT_API void setTextureTess ( TextureTess* texture_tess );
      /*!
       * \return the texture coordinate tesselation object.
       */
      OGLFT_API TextureTess* textureTess ( void ) const { return texture_tess_; }
  
      /*!
       * \return the height (i.e., line spacing) at the current character size.
       */
      OGLFT_API double height ( void ) const;
  
      /*!
       * Implement measuring a character in a polygonal face.
       * \param c the (latin1) character to measure
       * \return the bounding box of c.
       */
      OGLFT_API BBox measure ( unsigned char c );
  #ifndef OGLFT_NO_QT
      /*!
       * Implement measuring a character in a polygonal face.
       * \param c the (UNICODE) character to measure
       * \return the bounding box of c.
       */
      OGLFT_API BBox measure ( const QChar c );
  #endif /* OGLFT_NO_QT */
      /*!
       * Measure a string of characters. Note: currently, this merely
       * calls Face's measure routine.
       * \param s string of (latin1) characters to measure
       * \return the bounding box of s.
       */
      OGLFT_API BBox measure ( const char* s ) { return Face::measure( s ); }
  #ifndef OGLFT_NO_QT
      /*!
       * Implement measuring a formatted number
       * \param format the format string
       * \param number to value to format
       * \return the bounding box of the formatted number
       */
      OGLFT_API BBox measure ( const QString& format, double number )
      { return Face::measure( format, number ); }
  #endif /* OGLFT_NO_QT */
  
    private:
      void init ( void );
      void setCharSize ( void );
      void setRotationOffset ( void );
      GLuint compileGlyph ( FT_Face face, FT_UInt glyph_index );
    protected:
      void clearCaches ( void );
    };
  
    //! Render text as a polygon outline.
    /*!
     * \image html outline_class.png
     * Text is drawn as an outline of each glyph. The contours are extracted
     * from the font file through FreeType. FreeType is used to scale the
     * contours to a given size. Usually the outline is drawn in the foreground
     * color, however, you can specify a ColorTess object to provide a color
     * for each vertex individually. You can also use
     * the per-glyph display list functionality to alter the attributes
     * of each glyph.
     *
     * The only complexity to this style is selecting the point size. Since
     * the outlines are drawn as a polygon, they are subject to the MODELVIEW
     * transformation. The point size is nominally chosen to be the same as a
     * raster image generated at the given resolution. Some experimentation
     * with point size and resolution may be necessary to achieve the desired
     * results.
     */
    class Outline : public Polygonal {
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Outline ( const char* filename, float point_size = 12,
  			FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Outline ( const FT_Byte* data_base, const FT_Long data_size,
  			float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Outline ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * The destructor doesn't do anything in particular.
       */
      ~Outline ( void );
    private:
      void init ( void );
      void renderGlyph ( FT_Face face, FT_UInt glyph_index );
      static int moveToCallback ( FT_Vector* to, Outline* outline );
      static int lineToCallback ( FT_Vector* to, Outline* outline );
      static int conicToCallback ( FT_Vector* control, FT_Vector* to, Outline* outline );
      static int cubicToCallback ( FT_Vector* control1, FT_Vector* control2,
  				 FT_Vector* to, Outline* outline );
    };
  
    //! Render text as a filled polygons.
    /*!
     * \image html filled_class.png
     * Each glyph is drawn as a filled polygon. The contours are extracted
     * from the font file through FreeType. FreeType is used to scale the
     * contours to the given size. Then the GLU tessellation routines are used
     * to tessellate the contours into polygons (well, triangles). By default,
     * these are drawn in GL_FILL polygon mode, but any other polygon mode
     * can be specified.
     *
     * Usually, the polygons are drawn only in the
     * foreground color, however, you may supply ColorTess and TextureTess
     * objects which can alter the color or texture coordinates of each
     * vertex individually. You can also use
     * the per-glyph display list functionality to alter the attributes
     * of each glyph.
     *
     * The only complexity to this style is selecting the point size. Since
     * the glyphs are drawn as polygons, they are subject to the viewing and
     * modeling transformations. The point size is nominally chosen to be the same
     * as a raster image generated at the given resolution. Some experimentation
     * with point size and resolution may be necessary to achieve the desired
     * results.
     */
    class Filled : public Polygonal {
      //! 3D tessellation of glyphs is accomplished through the standard GLU
      //! routines
      GLUtesselator* tess_obj_;
  
      //! A place to store any extra vertices generated by the Combine callback
      VertexInfoList extra_vertices_;
  
    protected:
      //! Offset the glyph in the Z direction. Solely for the Solid subclass.
      //! Until I can figure out how to shift the glyph outside the context
      //! of this class, I guess this has got to stay (but it is redundant
      //! to extrusion_.depth_)
      GLfloat depth_offset_;
  
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Filled ( const char* filename, float point_size = 12,
  		       FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Filled ( const FT_Byte* data_base, const FT_Long data_size,
  		       float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Filled ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
      /*!
       * The destructor deletes the GLU tessellation object allocated in
       * in the constructor.
       */
      OGLFT_API virtual ~Filled ( void );
  
      /*!
       * \return the list of extra vertices created by the GLU tessellation
       * combine callback.
       */
      OGLFT_API VertexInfoList& extraVertices ( void ) { return extra_vertices_; }
  
    protected:
      void renderGlyph ( FT_Face face, FT_UInt glyph_index );
    private:
      void init ( void );
      static int moveToCallback ( FT_Vector* to, Filled* filled );
      static int lineToCallback ( FT_Vector* to, Filled* filled );
      static int conicToCallback ( FT_Vector* control, FT_Vector* to, Filled* filled);
      static int cubicToCallback ( FT_Vector* control1, FT_Vector* control2,
  				 FT_Vector* to, Filled* filled );
      static void vertexCallback ( VertexInfo* vertex );
      static void beginCallback ( GLenum which );
      static void endCallback ( void );
      static void combineCallback ( GLdouble coords[3], void* vertex_data[4],
  				  GLfloat weight[4], void** out_data,
  				  Filled* filled );
      static void errorCallback ( GLenum error_code );
    };
  
  #ifndef OGLFT_NO_SOLID
    //! Render text as solid letters.
    /*!
     * \image html solid_class.png
     * Each glyph is drawn as a closed solid. The contours are extracted
     * from the font file through FreeType. FreeType is used to scale the
     * contours to the given size. The contours are passed to the GLE
     * tubing and extrusion library to create the sides of the solid.
     * Then the GLU tessellation routines are used
     * to tessellate the contours into polygons which are used to cap the sides.
     *
     * Currently, the solids are drawn only in the foreground color. However,
     * proper surface normals are computed so that the solids may be lighted.
     * Eventually, you'll be able to supply a color/texture
     * coordinate function to make glyphs more interesting. Note that you can use
     * the per-glyph display list functionality to alter each glyph individually.
     *
     * Another TODO item is to improve the interaction with GLE. Currently,
     * you can only create block solids. Eventually, we'll have the capability
     * add bevels and rounds to the edges of the solids and maybe even more
     * general extrusions (like, for example, the swooshing letters in the title
     * sequence of the Salkind's 1978 "Superman" movie).
     *
     * The only complexity to this style is selecting the point size. Since
     * the glyphs are drawn as a collection of polygons, they are subject to the
     * viewing and modeling transformations. The point size is nominally chosen
     * to be the same as a raster image generated at the given resolution.
     * Some experimentation with point size and resolution may be necessary to
     * achieve the desired results.
     */
    class Solid : public Filled {
    private:
  
      //! Callbacks for FreeType glyph decomposition into outlines (note: this
      //! has the same name as the variable in Polygonal, but it is distinct since
      //! the routines for the GLE contouring are different from the Filled
      //! GLU tessellation routines. This may be too confusing?)
      FT_Outline_Funcs interface_;
  
      //! For now, you can only get block extruded solids
      static const unsigned int N_POLYLINE_PTS = 4;
  
      //! Data for the gleExtrusion routine
      struct glePoint2D {
        double p_[2];
        glePoint2D ( double p[2] ) { p_[X] = p[X]; p_[Y] = p[Y]; }
        glePoint2D ( double x, double y ) { p_[X] = x; p_[Y] = y; }
        glePoint2D ( const VertexInfo& v ) { p_[X] = v.v_[X]; p_[Y] = v.v_[Y]; }
      };
  
      //! Collect all the output from GLE in one of these structures.
      struct {
        double depth_;
        struct {
  	int x_, y_;
        } normal_sign_;
        std::vector< glePoint2D > contour_;
        std::vector< glePoint2D > contour_normals_;
        gleDouble up_[3];
        int n_polyline_pts_;
        gleDouble point_array_[N_POLYLINE_PTS][3];
      } extrusion_;
  
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Solid ( const char* filename, float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Solid ( const FT_Byte* data_base, const FT_Long data_size,
  		      float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Solid ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * The destructor doesn't do anything in particular.
       */
      OGLFT_API ~Solid ( void );
      /*!
       * Set the thickness of the solid
       * \param depth thickness of the solid in model units.
       */
      OGLFT_API void setDepth ( double depth );
  
      /*!
       * \return the solid extrusion depth.
       */
      OGLFT_API double depth ( void ) const { return extrusion_.depth_; }
  
    private:
      // It would be nice if C/C++ had real matrix notation (like Perl!)
      void assign ( gleDouble a[3], double x, double y, double z )
      {
        a[X] = x;
        a[Y] = y;
        a[Z] = z;
      }
  
      void init ( void );
      void renderGlyph ( FT_Face face, FT_UInt glyph_index );
      static int moveToCallback ( FT_Vector* to, Solid* solid );
      static int lineToCallback ( FT_Vector* to, Solid* solid );
      static int conicToCallback ( FT_Vector* control, FT_Vector* to, Solid* solid );
      static int cubicToCallback ( FT_Vector* control1, FT_Vector* control2,
  				 FT_Vector* to, Solid* solid );
    };
  #endif /* OGLFT_NO_SOLID */
    //! This is the base class of the raster styles: bitmap, grayscale and
    //! translucent.
    /*!
     * In the raster styles, FreeType's rasterizer is used to generate raster
     * images of each glyph.
     */
    class Raster : public Face {
    protected:
      //! Raster glyph can be rotated in the Z plane (in addition to the string
      //! rotation).
      GLfloat character_rotation_z_;
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Raster ( const char* filename, float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Raster ( const FT_Byte* data_base, const FT_Long data_size,
  		       float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Raster ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
      /*!
       * The destructor doesn't do anything in particular.
       */
      OGLFT_API virtual ~Raster ( void );
      /*!
       * Set the individual character rotation in the Z direction.
       * \param character_rotation_z angle in degrees of Z rotation.
       */
      OGLFT_API void setCharacterRotationZ ( GLfloat character_rotation_z );
      /*!
       * \return the character rotation in the Z direction.
       */
      OGLFT_API GLfloat characterRotationZ ( void ) const { return character_rotation_z_; }
  
      /*!
       * \return the height (i.e., line spacing) at the current character size.
       */
      OGLFT_API double height ( void ) const;
  
      /*!
       * Implement measuring a character in a raster face.
       * \param c the (latin1) character to measure
       * \return the bounding box of c.
       */
      OGLFT_API BBox measure ( unsigned char c );
  #ifndef OGLFT_NO_QT
      /*!
       * Implement measuring a character in a raster face.
       * \param c the (UNICODE) character to measure
       * \return the bounding box of c.
       */
      OGLFT_API BBox measure ( const QChar c );
  #endif /* OGLFT_NO_QT */
      /*!
       * Measure a string of characters. Note: currently, this merely
       * calls Face's measure routine.
       * \param s string of (latin1) characters to measure
       * \return the bounding box of s.
       */
      OGLFT_API BBox measure ( const char* s ) { return Face::measure( s ); }
  #ifndef OGLFT_NO_QT
      /*!
       * Implement measuring a formatted number
       * \param format the format string
       * \param number to value to format
       * \return the bounding box of the formatted number
       */
      OGLFT_API BBox measure ( const QString& format, double number );
  #endif /* OGLFT_NO_QT */
  
    private:
      void init ( void );
      GLuint compileGlyph ( FT_Face face, FT_UInt glyph_index );
      void setCharSize ( void );
      void setRotationOffset ( void );
      void clearCaches ( void );
    };
  
    //! Render text as a monochrome raster image.
    /*!
     * \image html monochrome_class.png
     * This is more or less the standard way in which text is intended to
     * be rendered in OpenGL. It uses the \c glBitmap call to draw a sequence
     * of monochrome bitmaps. Since FreeType is capable of rotating glyphs
     * created from faces based on vector outlines, you can rotate (in the Z plane)
     * both the text string as well as the individual characters in the string.
     *
     * Note: you \em must call
     * \code
     * glPixelStorei( GL_UNPACK_ALIGNMENT, 1 );
     * \endcode
     * before drawing in order for monochrome glyphs to be rendered properly.
     *
     * Another note: It is helpful to have the option
     * \c GL_RASTER_POSITION_UNCLIPPED_IBM available if you intend to draw text
     * at MODELVIEW based positions, otherwise if the initial text position is off
     * the screen, the entire image is clipped.
     */
    class Monochrome : public Raster {
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Monochrome ( const char* filename, float point_size = 12,
  			   FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Monochrome ( const FT_Byte* data_base, const FT_Long data_size,
  			   float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param font open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Monochrome ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
      /*!
       * The destructor doesn't do anything in particular.
       */
      OGLFT_API ~Monochrome ( void );
    private:
      GLubyte* invertBitmap ( const FT_Bitmap& bitmap );
      void renderGlyph ( FT_Face face, FT_UInt glyph_index );
    };
  
    //! Render text as a grayscale raster image.
    /*!
     * \image html grayscale_class.png
     * The Grayscale style is similar to the Monochrome style. FreeType is used
     * to rasterize a glyph and this is then drawn on the screen using
     * \c glDrawPixels. The FreeType rasterization is done in anti-aliased mode.
     * When Grayscale draws the glyph image, the resulting text is blended
     * smoothly from the foreground color to the background color. The background
     * of the glyph is opaque, so this style works best over a solid background.
     *
     * Note: you \em must call
     * \code
     * glPixelStorei( GL_UNPACK_ALIGNMENT, 1 );
     * \endcode
     * before drawing in order for grayscale glyphs to be rendered properly.
     *
     * Another note: It is helpful to have the option
     * \c GL_RASTER_POSITION_UNCLIPPED_IBM available if you intend to draw text
     * at MODELVIEW based positions, otherwise if the initial text position is off
     * the screen, the entire image is clipped.
     */
    class Grayscale : public Raster {
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Grayscale ( const char* filename, float point_size = 12,
  			  FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Grayscale ( const FT_Byte* data_base, const FT_Long data_size,
  			  float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Grayscale ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
      /*!
       * The destructor doesn't do anything in particular.
       */
      OGLFT_API ~Grayscale ( void );
    private:
      GLubyte* invertPixmap ( const FT_Bitmap& bitmap );
      void renderGlyph ( FT_Face face, FT_UInt glyph_index );
    };
  
    //! Render text as a translucent raster image.
    /*!
     * \image html translucent_class.png
     * The Translucent style is similar to the Grayscale style. FreeType is used
     * to rasterize a glyph and this is then drawn on the screen using
     * \c glDrawPixels. The FreeType rasterization is done in anti-aliased mode.
     * When Translucent draws the glyph image, the grayscale levels provided
     * by FreeType are used as Alpha values in the raster image. This allows
     * the glyphs to be smoothly blended into complicated backgrounds.
     *
     * Note: you \em must call
     * \code
     * glPixelStorei( GL_UNPACK_ALIGNMENT, 1 );
     * \endcode
     * before drawing in order for translucent glyphs to be rendered properly.
     * Additionally, you need to activate blending in order to achieve the
     * translucent effect:
     * \code
     * glEnable( GL_BLEND );
     * glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
     * \endcode
     *
     * Another note: It is helpful to have the option
     * \c GL_RASTER_POSITION_UNCLIPPED_IBM available if you intend to draw text
     * at MODELVIEW based positions, otherwise if the initial text position is off
     * the screen, the entire image is clipped.
     */
    class Translucent : public Raster {
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Translucent ( const char* filename, float point_size = 12,
  			    FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Translucent ( const FT_Byte* data_base, const FT_Long data_size,
  			    float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Translucent ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * The destructor doesn't do anything in particular.
       */
      OGLFT_API ~Translucent ( void );
  
    private:
      GLubyte* invertPixmapWithAlpha ( const FT_Bitmap& bitmap );
      void renderGlyph ( FT_Face face, FT_UInt glyph_index );
    };
  
    //! This is the base class of the texture style.
    class Texture : public Face {
    protected:
      //! Angle of rotation of characters relative to text orientation.
      struct {
        bool active_; //!< Is character rotation non-zero? (faster than checking all
  		    //!< the other values.)
        GLfloat x_,   //!< Angle of rotation in the X direction.
  	y_,	    //!< Angle of rotation in the Y direction.
  	z_;	    //!< Angle of rotation in the Z direction.
      } character_rotation_;
  
      /*!
       * The textured glyphs need a little bit more infrastructure to draw
       * since we have to remember the size of the texture object itself
       * (at least implicitly). Also, we don't want to create any more
       * texture objects than we have to, so they are always cached.
       */
      struct TextureInfo {
        GLuint texture_name_;  //!< A bound texture name is an integer in OpenGL.
        FT_Int left_bearing_,  //!< The left bearing of the transformed glyph.
  	bottom_bearing_;     //!< The bottom bearing of the transformed glyph.
        int width_,	     //!< The 2**l width of the texture.
  	height_;	     //!< The 2**m height of the texture.
        GLfloat texture_s_,    //!< The fraction of the texture width occupied
  			     //!< by the glyph.
  	texture_t_;	     //!< The fraction of the texture height occupied
                               //!< by the glyph.
        FT_Vector advance_;    //!< The advance vector of the transformed glyph.
      };
  
      //! Type of the cache of defined glyph to texture objects mapping.
      typedef std::map< FT_UInt, TextureInfo > GlyphTexObjs;
  
      //! A convenience definition of the iterator over the glyph to texture
      //! object map.
      typedef GlyphTexObjs::const_iterator GTOCI;
  
      //! A convenience definition of the iterator over the glyph to texture
      //! object map.
      typedef GlyphTexObjs::iterator GTOI;
  
      //! Cache of defined glyph texture objects.
      GlyphTexObjs glyph_texobjs_;
  
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Texture ( const char* filename, float point_size = 12,
  			FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Texture ( const FT_Byte* data_base, const FT_Long data_size,
  			float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API Texture ( FT_Face face, float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * The texture destructor doesn't really do anything.
       */
      OGLFT_API virtual ~Texture ( void );
      /*!
       * Set the individual character rotation in the X direction.
       * \param character_rotation_x angle in degrees of X rotation.
       */
      OGLFT_API void setCharacterRotationX ( GLfloat character_rotation_x );
  
      /*!
       * Set the individual character rotation in the Y direction.
       * \param character_rotation_y angle in degrees of Y rotation.
       */
      OGLFT_API void setCharacterRotationY ( GLfloat character_rotation_y );
  
      /*!
       * Set the individual character rotation in the Z direction.
       * \param character_rotation_z angle in degrees of Z rotation.
       */
      OGLFT_API void setCharacterRotationZ ( GLfloat character_rotation_z );
  
      /*!
       * \return the character rotation in the X direction.
       */
      OGLFT_API GLfloat characterRotationX ( void ) const { return character_rotation_.x_; }
  
      /*!
       * \return the character rotation in the Y direction.
       */
      OGLFT_API GLfloat characterRotationY ( void ) const { return character_rotation_.y_; }
  
      /*!
       * \return the character rotation in the Z direction.
       */
      OGLFT_API GLfloat characterRotationZ ( void ) const { return character_rotation_.z_; }
  
      /*!
       * \return the height (i.e., line spacing) at the current character size.
       */
      OGLFT_API double height ( void ) const;
  
      /*!
       * Implement measuring a character in a texture face.
       * \param c the (latin1) character to measure
       * \return the bounding box of c.
       */
      OGLFT_API BBox measure ( unsigned char c );
  #ifndef OGLFT_NO_QT
      /*!
       * Implement measuring a character in a texture face.
       * \param c the (UNICODE) character to measure
       * \return the bounding box of c.
       */
      OGLFT_API BBox measure ( const QChar c );
  #endif /* OGLFT_NO_QT */
      /*!
       * Measure a string of characters. Note: currently, this merely
       * calls Face's measure routine.
       * \param s string of (latin1) characters to measure
       * \return the bounding box of s.
       */
      OGLFT_API BBox measure ( const char* s ) { return Face::measure( s ); }
  #ifndef OGLFT_NO_QT
      OGLFT_API BBox measure ( const QString& s )
      { return Face::measure( s ); }
  
      /*!
       * Implement measuring a formatted number
       * \param format the format string
       * \param number to value to format
       * \return the bounding box of the formatted number
       */
      OGLFT_API BBox measure ( const QString& format, double number )
      { return Face::measure( format, number ); }
  #endif /* OGLFT_NO_QT */
  
    protected:
      /*!
       * OpenGL texture maps have to be a power of 2 in width and height (including
       * apparently 1 = 2**0 ). This function returns the next higher power of
       * 2 of the argument. If the argument is already a power of 2, you just
       * get that back.
       * \param a width or height of an image.
       * \return value of a rounded to nearest, higher power of 2.
       */
      unsigned int nearestPowerCeil ( unsigned int a );
      /*!
       * This is all that distinguishes the various texture styles. Each subclass
       * defines this method as appropriate. Once the texture is bound, it
       * is rendered the same in all cases.
       * \param face FT_Face containing the glyph to render.
       * \param glyph_index index of glyph in face.
       */
      virtual void bindTexture ( FT_Face face, FT_UInt glyph_index ) = 0;
  
    private:
      void init ( void );
      void setCharSize ( void );
      void setRotationOffset ( void );
      GLuint compileGlyph ( FT_Face face, FT_UInt glyph_index );
      void renderGlyph ( FT_Face face, FT_UInt glyph_index );
      void clearCaches ( void );
    };
  
    //! Render text as texture mapped monochrome quads.
    /*!
     * \image html texture_monochrome_class.png
     * This style is similar to the Monochrome raster style, except instead
     * of using \c glBitmap to draw the raster image, the image is used
     * as a texture map on a quad. If drawing is confined to the Z plane,
     * then you will see no difference between this style and Monochrome.
     * However, because the quad is a 3D object, it can be transformed
     * by the usual modeling operations; so, texture mapped glyphs can be
     * rotated in the X and Y directions as well as Z direction. Also,
     * if the viewing (or modeling) transformation has a non-unity scale or
     * shear, the glyphs will also be scaled or sheared (unlike the raster
     * styles). Also, there is no problem with clipping glyphs which lie
     * off the screen; texture mapped quads are properly clipped to the
     * screen boundary.
     *
     * If this is not convincing enough, the performance of texture mapped
     * glyphs is generally as good as or better than the equivalent
     * raster style (especially with hardware texture acceleration). However,
     * they do take up more memory space.
     *
     * Note: you \em must call
     * \code
     * glPixelStorei( GL_UNPACK_ALIGNMENT, 1 );
     * \endcode
     * before drawing in order for textured glyphs to be rendered properly.
     */
    class MonochromeTexture : public Texture {
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API MonochromeTexture ( const char* filename, float point_size = 12,
  				  FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API MonochromeTexture ( const FT_Byte* data_base, const FT_Long data_size,
  				  float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API MonochromeTexture ( FT_Face face, float point_size = 12,
  				  FT_UInt resolution = 100 );
      /*!
       * The monochrome texture destructor doesn't really do anything.
       */
      OGLFT_API ~MonochromeTexture ( void );
    private:
      GLubyte* invertBitmap ( const FT_Bitmap& bitmap, int* width, int* height );
      void bindTexture ( FT_Face face, FT_UInt glyph_index );
    };
  
    //! Render text as texture mapped grayscale quads.
    /*!
     * \image html texture_grayscale_class.png
     * This style is similar to the Grayscale raster style, except instead
     * of using \c glDrawPixels to draw the raster image, the image is used
     * as a texture map on a quad. If drawing is confined to the Z plane,
     * then you will see no difference between this style and Grayscale.
     * However, because the quad is a 3D object, it can be transformed
     * by the usual modeling operations; so, texture mapped glyphs can be
     * rotated in the X and Y directions as well as Z direction. Also,
     * if the viewing (or modeling) transformation has a non-unity scale or
     * shear, the glyphs will also be scaled or sheared (unlike the raster
     * styles). Also, there is no problem with clipping glyphs which lie
     * off the screen; texture mapped quads are properly clipped to the
     * screen boundary.
     *
     * If this is not convincing enough, the performance of texture mapped
     * glyphs is generally as good as or better than the equivalent
     * raster style (especially with hardware texture acceleration). However,
     * they do consume more memory space.
     *
     * Note: you \em must call
     * \code
     * glPixelStorei( GL_UNPACK_ALIGNMENT, 1 );
     * \endcode
     * before drawing in order for textured glyphs to be rendered properly.
     */
    class GrayscaleTexture : public Texture {
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API GrayscaleTexture ( const char* filename, float point_size = 12,
  				 FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API GrayscaleTexture ( const FT_Byte* data_base, const FT_Long data_size,
  				 float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API GrayscaleTexture ( FT_Face face, float point_size = 12,
  				 FT_UInt resolution = 100 );
      /*!
       * The grayscale texture destructor doesn't really do anything.
       */
      OGLFT_API ~GrayscaleTexture ( void );
    private:
      GLubyte* invertPixmap ( const FT_Bitmap& bitmap, int* width, int* height );
      void bindTexture ( FT_Face face, FT_UInt glyph_index );
    };
  
    //! Render text as texture mapped translucent quads.
    /*!
     * \image html texture_translucent_class.png
     * This style is similar to the Translucent raster style, except instead
     * of using \c glDrawPixels to draw the raster image, the image is used
     * as a texture map on a quad. If drawing is confined to the Z plane,
     * then you will see no difference between this style and Translucent.
     * However, because the quad is a 3D object, it can be transformed
     * by the usual modeling operations; so, texture mapped glyphs can be
     * rotated in the X and Y directions as well as Z direction. Also,
     * if the viewing (or modeling) transformation has a non-unity scale or
     * shear, the glyphs will also be scaled or sheared (unlike the raster
     * styles). Also, there is no problem with clipping glyphs which lie
     * off the screen; texture mapped quads are properly clipped to the
     * screen boundary.
     *
     * If this is not convincing enough, the performance of texture mapped
     * glyphs is generally as good as or better than the equivalent
     * raster style (especially with hardware texture acceleration). However,
     * they do consume more memory space.
     *
     * Note: you \em must call
     * \code
     * glPixelStorei( GL_UNPACK_ALIGNMENT, 1 );
     * \endcode
     * before drawing in order for textured glyphs to be rendered properly.
     * Additionally, you need to activate blending in order to achieve the
     * translucent effect:
     * \code
     * glEnable( GL_BLEND );
     * glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
     * \endcode
     */
    class TranslucentTexture : public Texture {
    public:
      /*!
       * \param filename the filename which contains the font face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API TranslucentTexture ( const char* filename, float point_size = 12,
  				   FT_UInt resolution = 100 );
  
      /*!
       * \param data_base the memory location (base pointer) which contains the font face.
       * \param data_size the size (in bytes) of the font data found at \ref data_base.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API TranslucentTexture ( const FT_Byte* data_base, const FT_Long data_size,
  				   float point_size = 12, FT_UInt resolution = 100 );
  
      /*!
       * \param face open FreeType FT_Face.
       * \param point_size the initial point size of the font to generate. A point
       * is essentially 1/72th of an inch. Defaults to 12.
       * \param resolution the pixel density of the display in dots per inch (DPI).
       * Defaults to 100 DPI.
       */
      OGLFT_API TranslucentTexture ( FT_Face face, float point_size = 12,
  				   FT_UInt resolution = 100 );
      /*!
       * The translucent texture destructor doesn't really do anything.
       */
      OGLFT_API ~TranslucentTexture ( void );
    private:
      GLubyte* invertPixmap ( const FT_Bitmap& bitmap, int* width, int* height );
      void bindTexture ( FT_Face face, FT_UInt glyph_index );
    };
  } // Close OGLFT namespace
  #endif /* OGLFT_H */
  